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Accompanied versus unaccompanied walking for continuous oxygen saturation measurement during 6-min walk test in COPD: A randomised cross-over study

Citation

Riegler, Thomas F.; Frei, Anja; Haile, Sarah R.; Radtke, Thomas (2021), Accompanied versus unaccompanied walking for continuous oxygen saturation measurement during 6-min walk test in COPD: A randomised cross-over study, Dryad, Dataset, https://doi.org/10.5061/dryad.gmsbcc2n7

Abstract

Is there is a difference in the 6-Minute Walk Test (6MWT) distance when the assessor accompanies the patient to continuously measure oxygen saturation (SpO2) compared to the patient walking unaccompanied?

We conducted a randomised cross-over study to evaluate the impact of the assessor walking with the patient during 6MWT (6MWTwith) versus patient walking alone (6MWTwithout). At the end of a pulmonary rehabilitation programme, each patient performed two 6MWTs in random order and separated by 30 minutes rest.

49 COPD patients (GOLD II-IV) were included. In a regression model adjusting for period and subject, accompanying the patient resulted in a lower walking distance (mean difference -9.1 m, [95%CI, -13.9 to -4.3], p=0.0004). Notably, six patients walked more than 30m further (minimal important difference, MID) in one of the two conditions (6MWTwith: n=1, 6MWTwithout: n=5). There were no betweensequence-group differences in heart rate, dyspnoea and leg-fatigue, and SpO2. The median (interquartile range) number and duration of SpO2 signal artefacts were high but not different between the experimental conditions (6MWTwith: 17 [4, 24], 34s [7, 113], 6MWTwithout: 11 [3, 26], 24s [4, 62]).

On a study population level, we observed a statistically significant difference in 6MWT distance between the two experimental conditions, however, the magnitude of difference is small and may not be considered clinically relevant. Nevertheless, in a clinical setting, unaccompanied walking resulted in a substantially higher walking distance in individual patients, pointing towards strictly standardised testing methodology, in particular in pre-post study designs.